upload-pack: convert to use reference_get_peeled_oid()

The `write_v0_ref()` callback is invoked from two callsites:

  - Once via `send_ref()` which is a callback passed to
    `for_each_namespaced_ref_1()` and `refs_head_ref_namespaced()`.

  - Once manually to announce capabilities.

When sending references to the client we also send the peeled value of
tags. As we don't have a `struct reference` available in the second
case, we cannot easily peel by calling `reference_get_peeled_oid()`, but
we instead have to depend on on global state via `peel_iterated_oid()`.

We do have a reference available though in the first case, it's only the
second case that keeps us from using `reference_get_peeled_oid()`. But
that second case only announces capabilities anyway, so we're not really
handling a reference at all here.

Adapt that case to construct a reference manually and pass that to
`write_v0_ref()`. Start to use `reference_get_peeled_oid()` now that we
always have a `struct reference` available.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pks-t

upload-pack.c

@@ -1249,15 +1249,15 @@ static void format_session_id(struct strbuf *buf, struct upload_pack_data *d) {
 }
 
 static void write_v0_ref(struct upload_pack_data *data,
-			const char *refname, const char *refname_nons,
-			const struct object_id *oid)
+			 const struct reference *ref,
+			 const char *refname_nons)
 {
 	static const char *capabilities = "multi_ack thin-pack side-band"
 		" side-band-64k ofs-delta shallow deepen-since deepen-not"
 		" deepen-relative no-progress include-tag multi_ack_detailed";
 	struct object_id peeled;
 
-	if (mark_our_ref(refname_nons, refname, oid, &data->hidden_refs))
+	if (mark_our_ref(refname_nons, ref->name, ref->oid, &data->hidden_refs))
 		return;
 
 	if (capabilities) {
@@ -1267,7 +1267,7 @@ static void write_v0_ref(struct upload_pack_data *data,
 		format_symref_info(&symref_info, &data->symref);
 		format_session_id(&session_id, data);
 		packet_fwrite_fmt(stdout, "%s %s%c%s%s%s%s%s%s%s object-format=%s agent=%s\n",
-			     oid_to_hex(oid), refname_nons,
+			     oid_to_hex(ref->oid), refname_nons,
 			     0, capabilities,
 			     (data->allow_uor & ALLOW_TIP_SHA1) ?
 				     " allow-tip-sha1-in-want" : "",
@@ -1283,17 +1283,17 @@ static void write_v0_ref(struct upload_pack_data *data,
 		strbuf_release(&session_id);
 		data->sent_capabilities = 1;
 	} else {
-		packet_fwrite_fmt(stdout, "%s %s\n", oid_to_hex(oid), refname_nons);
+		packet_fwrite_fmt(stdout, "%s %s\n", oid_to_hex(ref->oid), refname_nons);
 	}
 	capabilities = NULL;
-	if (!peel_iterated_oid(the_repository, oid, &peeled))
+	if (!reference_get_peeled_oid(the_repository, ref, &peeled))
 		packet_fwrite_fmt(stdout, "%s %s^{}\n", oid_to_hex(&peeled), refname_nons);
 	return;
 }
 
 static int send_ref(const struct reference *ref, void *cb_data)
 {
-	write_v0_ref(cb_data, ref->name, strip_namespace(ref->name), ref->oid);
+	write_v0_ref(cb_data, ref, strip_namespace(ref->name));
 	return 0;
 }
 
@@ -1442,8 +1442,12 @@ void upload_pack(const int advertise_refs, const int stateless_rpc,
 					 send_ref, &data);
 		for_each_namespaced_ref_1(send_ref, &data);
 		if (!data.sent_capabilities) {
-			const char *refname = "capabilities^{}";
-			write_v0_ref(&data, refname, refname, null_oid(the_hash_algo));
+			struct reference ref = {
+				.name = "capabilities^{}",
+				.oid = null_oid(the_hash_algo),
+			};
+
+			write_v0_ref(&data, &ref, ref.name);
 		}
 		/*
 		 * fflush stdout before calling advertise_shallow_grafts because send_ref